Major Sesame diseases are given below:-
1.Bacterial blight: Xanthomonas campestris pv. sesami
Symptom:
- Plants of all stage are affected.
- Water soaked, small and irregular spots are formed on the leaves which later increases and turn brown, under favourable conditions.
- Leaves become dry and brittle, severely infected leaves defoliate.
Management:
- Crop rotation.
- Use resistant variety like T-58
- Early planting i.e. immediately after onset of monsoon.
- Destruction of crop residues.
- Steep the seed in Agrimycin-100 (250 ppm) or Streptocycline suspension (0.05%) for 30 minutes.
- Foliar spray of Streptocycline (500 ppm) as soon as symptoms are noticed.
- Continue two more sprays at 15 days interval if necessary.
2.Cercospora leaf spot / White spot: Cercospora sesami, C. sesamicola
Symptom:
- The disease appears as small, angular brown leaf spots of 3 mm diameter with a grey centre and dark margin delimited by veins.
- In severity of the disease defoliation occurs. Under favourable conditions, the disease spreads to leaf petiole, stem and capsules producing linear dark coloured deep seated lesions.
Management:
- Spray Mancozeb 1000g/ha
3.Damping off / Root Rot: Macrophomina phaseolina
Symptom:
- The fungus attacks young seedling, their stem becomes water soaked soft and incapable of supporting the seedling which falls over and dies.
- On older seedlings elongated brownish black lesions appear which increase in length and width girdling the stem and plant dies.
Management:
- Soil application of P. fluorescens or T. viride – 2.5 Kg / ha + 50 Kg of well decomposed FYM or sand at 30 days after sowing.
- Spot drench Carbendazim – 1 gm/ litre.
4.Powdery mildew: Oidium sp., Sphaerotheca fuliginia, Leveillula sp.
Symptom:
- Small cottony spots appear on the infected leaves which gradually spread on the lamina.
- Defoliation of severely infected plant occurs before maturity.
Management:
- Apply any one of the following Sulphur dust 25 kg/ha Wettable sulphur 25 kg/ha
5.Sesamum phyllody: Phytoplasma
Symptom:
- All floral parts are transformed into green leafy structures followed by abundant vein clearing in different flower parts.
- In severe infection, the entire inflorescences is replaced by short twisted leaves closely arranged on a stem with short internodes, abundant abnormal branches bend down.
- Finally, plants look like a witches broom.
- If capsules are formed on lower portion of plant they do not yield quality seeds.
- Transmitted by the vector Orosius albicintus
Management:
- Remove and destroy infected plants.
- To control vector, spray Monocrotophos 36 or Dimethoate 30 EC 500 ml/ha combined with intercropping of Sesamum + Redgram (6: 1)
6.Root rot: Fusarium oxysporum f.sp.sesami
Symptom:
- The plant gets infected at any stage of crop development.
- Symptoms are first visible on the lower leaves and then it progresses upwards.
- Yellowing, drooping and desiccation of leaves occur.
- In a severe case, the entire plant gets defoliated, bends down and ultimately dries up.
- Vascular bundles turn brown starting from the root and get extended up to tip.
Management:
- Deep ploughing in summer.
- Follow crop rotation
- Soil amendment with farm yard manure @ 12.5 tonnes/ha is helpful in reducing the incidence of the disease
- Destroy the diseased plant debris by burning of burying in the soil.
- Seed treatment with T. viride @4g/kg or P. fluorescens @ 10g/ kg of seed or Carbendazim or Thiram 2g/kg of seed.
- Spot drenching with Carbendazim 1g/lit.
- Soil application of P. fluorescens / T. viride 2.5 kg/ha with 50 kg FYM.
Source-
- TamilNadu Agritech Portal
